A point light source (PLS) display with enhanced viewing angle (VA) is proposed. The maximum VA of a conventional PLS display is equal to the propagation angle of the PLS, so a light-source array (3×3) was used to enlarge the propagation angle of the PLS in the horizontal and vertical directions. The number of converging elemental image points increases due to the large propagation angle of the PLS; thus, the VA of the integrated point was enhanced. From the experimental results, the VA of the proposed method was 2.6 times larger than the maximum VA of a conventional PLS display.

A novel method of viewing angle enhancement of a real-time integral imaging system using multi-directional projections and GPU parallel processing is proposed. The proposed system is composed of three processes: information acquisition of real objects, generation of multi-directional elemental image sets, and reconstruction of 3D images by using multidirectional projections scheme. To implement this system, depth and color (RGB) information of each object point are captured by a depth camera; then, a dynamic algorithm and GPU parallel processing are used for generating multidirectional elemental image sets to be illuminated in different directions as well as to maintain a real-time processing seed; and finally, 3D images are reconstructed by using a time-multiplexed multi-directional projection scheme through an appropriate optical setup of a projection-type integral image system. Multi-directional illuminations of elemental image sets enhance the optical ray divergence of reconstructed 3D images according to the directional projection angles. Hence, a real-time integral imaging system with enhanced viewing angle is achieved.

An integral imaging system using a polygon model for a real object is proposed. After depth and color data of the real object are acquired by a depth camera, the grid of the polygon model is converted from the initially reconstructed point cloud model. The elemental image array is generated from the polygon model and directly reconstructed. The polygon model eliminates the failed picking area between the points of a point cloud model, so at least the quality of the reconstructed 3-D image is significantly improved. The theory is verified experimentally, and higher-quality images are obtained.

We propose an optical design of cipher block chaining (CBC) encryption by using digital holographic technique,
which has higher security than the conventional electronic method because of the analog-type randomized cipher text
with 2-D array. In this paper, an optical design of CBC encryption mode is implemented by 2-step quadrature phase-shifting
digital holographic encryption technique using orthogonal polarization. A block of plain text is encrypted with
the encryption key by applying 2-step phase-shifting digital holography, and it is changed into cipher text blocks which
are digital holograms. These ciphered digital holograms with the encrypted information are Fourier transform holograms
and are recorded on CCDs with 256 gray levels quantized intensities. The decryption is computed by these encrypted
digital holograms of cipher texts, the same encryption key and the previous cipher text. Results of computer simulations
are presented to verify that the proposed method shows the feasibility in the high secure CBC encryption system.

A novel 360-degree integral-floating display based on the real object is proposed. The general procedure of the display system is similar with conventional 360-degree integral-floating displays. Unlike previously presented 360-degree displays, the proposed system displays the 3D image generated from the real object in 360-degree viewing zone. In order to display real object in 360-degree viewing zone, multiple depth camera have been utilized to acquire the depth information around the object. Then, the 3D point cloud representations of the real object are reconstructed according to the acquired depth information. By using a special point cloud registration method, the multiple virtual 3D point cloud representations captured by each depth camera are combined as single synthetic 3D point cloud model, and the elemental image arrays are generated for the newly synthesized 3D point cloud model from the given anamorphic optic system’s angular step. The theory has been verified experimentally, and it shows that the proposed 360-degree integral-floating display can be an excellent way to display real object in the 360-degree viewing zone.

We proposed a novel scheme to achieve a computer-generated hologram (CGH). The CGH is generated from a point cloud that is transformed by a mapping relationship of a series of sub-images. The sub-images are converted from elemental images captured by integral imaging pickup system. A more continues depth map can be obtained and a clearer display of the 3D scene can be presented. Moreover, the inherent drawback pseudoscopic problem of integral imaging can also be overcome.

In this paper, the design and produce of the wedge-shaped waveguide head-mounted display (HMD) based on reflection holographic optical element (RHOE) are described. A variety of factors were considered when designing, such as loss of efficiency, volume, wide field of view (FOV), and eye box. The thickness of the designed wedge-shaped waveguide can be reduced to two times in comparison with the system that uses the conventional reflective optics in the waveguide. The measured optical efficiency of the monocular HMD using HOE is 34%, with 15° FOV and a large eye box. The results confirm that the designed and fabricated waveguide can be employed in future commercial HMD.

Holographic optical element (HOE) have classically been designed using grating theory, logically so, since an HOE is a grating produced on film by two interfering beams of coherent light. This paper describes the development of full color HOE recorded on aspherical substrate using a photopolymer. The reflection HOE was evaluated by measuring the diffraction efficiencies of holographic volume gratings recorded individually at 633 nm, 532 nm, and 473nm wavelengths. The spectral characterization of the HOE, recorded using a combined single beam, and recorded using sequential beam, was carried out. Practical methods for fabrication of high efficiency aspheric HOE by single layer photopolymer were developed.

In this paper we present the method for fast computer generation hologram (CGH) of the long depth object using multiple wavefront recording planes (WRP). The wavefront recording planes are placed between object plane and hologram plane. Each WRP records the wavefront from a section of object. For a long depth object, multiple WRPs can reduce the calculation time and also enhance the quality of reconstruction object in comparison with those ones of single WRP. The hologram of object can be real time generated by out proposed method.

Viewing angle enhanced integral imaging (II) system using multi-directional projections and elemental image (EI) resizing method is proposed. In this method, each elemental lens of micro lens array collects multi-directional illuminations of multiple EI sets and produces multiple point light sources (PLSs) at the different positions in the focal plane; and the positions of the PLSs can be controlled by the projection angles. The viewing zone is made consisting of multiple diverging ray bundles, wider than the conventional method, due to multi-directional projections of multiple EI sets; whereas a conventional system produces a viewing zone using only a single set of EI projection. Hence the viewing angle of the reconstructed image is enhanced.

We proposed a fast scheme for computer-generated holography (CGH) to mix 3D scenes. The objects in the proposed include the real and virtual objects. Make a point cloud model of real object, and then converted to a triangular mesh model. And mix the triangular mesh model with virtual 3D object mesh models. Using the angular spectrum method to generated hologram, and it is convenient to accelerating with GPU.

In this paper, we present the development of full color holographic optical element for light-emitting diodes display application using a photopolymer. The reflection HOE was evaluated by measuring the diffraction efficiencies of holographic volume gratings recorded individually at 633 nm, 532 nm, and 473nm wavelengths. The spectral characterization of the holographic optical element, recorded using a combined single beam, and recorded using sequential beam, was carried out. Practical methods for fabrication of high efficiency holographic optical element by single layer photopolymer were developed. As the reconstruction light source of the hologram, light-emitting diodes of 632nm, 523nm and 465nm in wavelength was used. The results represent a strong confirmation that the special recording method using photopolymer can be employed in future commercial holographic applications.

Viewing angle of the conventional flat hologram is not very large (less than 180°) attributed to their planar observation surface. If we want to synthesize a wide view computer generated hologram, a numerical simulation of the diffraction on the non-planar observation surfaces is required, computer generated cylindrical hologram (CGCH) can be a solution. Approximately 2,500 object points were used for this research. We have realized a CGCH that is viewable in 360°. However, the heavy computation load is one of the issues. Therefore, we propose a fast calculation method for a computer generated cylindrical hologram by the use of wave-front recording surface. The wave-front recording surface is placed between the object data and a CGCH. When the wave-front recording surface is placed close to the object, the object light passes through a small region on the wave recording surface. Therefore the computational complexity for the object light is very small. We can obtain a CGCH to execute diffraction calculation from the wave-front recording surface, propagating the recorded optical field of the wave-front recording surface to the cylindrical hologram surface using only two FFT operations and hence is much faster.

A depth camera has been used to capture the depth data and color data for real-world objects. As an integral imaging display system is broadly used, the elemental image array for the captured data needs to be generated and displayed on liquid crystal display. We proposed a real-time integral imaging display system using image processing to simplify the optical arrangement and graphics processing unit parallel processing to reduce the time for computation. The proposed system provides elemental images generated at a rate of more than 30 fps with a resolution of 1204×1204 pixels , where the size of each display panel pixel was 0.1245 mm, and an array of 30×30 lenses , where each lens was 5×5 mm .

In this paper an application of the Holographic Optical Element (HOE) which is designed by using the photopolymer is
proposed. Using the HOE to replace two optic elements of the conventional HMD is possible to reduce the volume and
weight. In order to implement the proposed system, we analyze the optical characteristics of the photopolymer and
confirm the optimum recording condition of the HOE. The proposed system is verified experimentally.

Holographic three dimensional (3D) parallel lithography using femtosecond laser pulse were demonstrated in this paper.
A computer generated hologram (CGH) that calculated using kinoform algorithm with optimal rotation angle (ORA)
method were used in order to increase the uniformity of the diffraction peaks so that the resolution of the 3D image also
improved. The use of femtosecond pulse duration of a Ti:sapphire laser improved the holograms resolution due to larger
peak powers that generate larger photonics concentrations at the beam focus and improve single-shot processing. A
digital instrument nanoscope was used to verify the result and scanning electron microscopy (SEM) will be used to
observe the detail result.

In this paper, we present an analysis on space bandwidth product of digital hologram. The condition for clear
reconstruction of in-axis and off-axis digital hologram case is derived. The correlation efficiency and modulate transfer
function (MTF) are then used for quantitative analysis of the reconstruction object. The presented analysis is verified by
simulation result and then is applied to record and reconstruct video hologram.

Three-dimensional holographic system using active shutters for head mounted display application is proposed.
Conventional three-dimensional head mounted display suffers from eye-fatigue since it only provides binocular
disparity, not monocular depth cues like accommodation. The proposed method presents two holograms of a 3D scene to
corresponding eyes using active shutters. Since a holography delivered to each eye has full three-dimensional
information, not only the binocular depth cues but also monocular depth cues are presented, eliminating eye-fatigue. The
application to the head mounted display also greatly relaxes the viewing angle requirement that is one of the main issues
of the conventional holographic displays. In presentation, the proposed optical system will be explained in detail with
experimental results.

We propose full-parallax integral imaging display with 360 degree horizontal viewing angle. Two-dimensional (2D)
elemental images are projected by a high-speed DMD projector and integrated into three-dimensional (3D) image by a
lens array. The anamorphic optic system tailors the horizontal and vertical viewing angles of the integrated 3D images in
order to obtain high angular ray density in horizontal direction and large viewing angle in vertical direction. Finally, the
mirror screen that rotates in synchronization with the DMD projector presents the integrated 3D images to desired
direction accordingly. Full-parallax and 360 degree horizontal viewing angle 3D images with both of monocular and
binocular depth cues can be achieved by the proposed method.

In this study we have exploited the parallel nature of the computations involved in the process of numerical volume
reconstruction of three-dimensional digital holographic microscopy and utilized CUDA enabled graphics processing
unit (GPU) to accelerate the reconstruction process. We have recorded holograms of the 3D specimen using CCD
with inline setup, then using GPU we have initiated CUDA kernels for de-convolution of the diffraction integral for
multiple depth planes in parallel, speeding up the reconstruction of the entire volume. Our experimental results
confirm that GPU reconstruction is much faster than that of central processing unit (CPU).

In the transformation based compression algorithms of digital hologram for three-dimensional object, the balance
between compression ratio and normalized root mean square (NRMS) error is always the core of algorithm development.
The wavelet transform method is efficient to achieve high compression ratio but NRMS error is also high. In order to
solve this issue, we propose a hologram compression method using Wavelet-Bandelets transform. Our simulation and
experimental results show that the Wavelet-Bandelets method has a higher compression ratio than Wavelet methods and
all the other methods investigated in this paper, while it still maintains low NRMS error.

Integral imaging captures three-dimensional information of the object scene by sampling the spatial and angular
distribution of the light rays. In this paper, we show several three-dimensional imaging techniques based on integral
imaging. First, principle of integral imaging and its basic three-dimensional visualization methods are explained. Then as
its application, a three-dimensional microscope is introduced. The three-dimensional information of the microscopic
specimen can be captured by applying the integral imaging principle to the conventional microscope. An extension of the
basic three-dimensional visualization is also explained to enhance the resolution of the arbitrary view reconstruction.
Three-dimensional information embedded in the captured ray distribution can also be exploited to synthesize the threedimensional
holography of the object, which provides an efficient way for incoherent holography capture. Finally, we
show an analysis of the sampling of the ray distribution. By analyzing the spatio-angular bandwidth of the ray space, the
optimum sampling strategy can be found.

A novel method to capture a Fourier holography of the three-dimensional objects under regular incoherent illumination is
proposed. Multiple images of the three-dimensional objects are captured by a camera while moving the focal plane along
the optic axis over the whole object space. Captured multiple defocused images are processed considering the point
spread function of the camera and the Fourier holography is finally synthesized. The principle is explained and verified
experimentally.

We propose a method for pickup and display of the microscopic object using confocal microscopy and integral imaging.
Instead of the conventional pickup process of integral imaging, we use a confocal microscopy to measure the three-dimensional
shape of the microscopic objects. The elemental images are then calculated from the measured three-dimensional
shape of the objects, considering the lens array specifications of the display process. Finally, three-dimensional
image of the microscopic object is displayed using integral imaging display process. The three-dimensional
model of the microscopic object constructed using confocal microscopy makes it possible to generate the elemental
images for any lens array specifications, providing the full freedom in configuring integral imaging display system. Also,
the generated elemental images are free from any distortions of the lens arrays, hence it enhances the quality of the
reconstructed three-dimensional images and enables the three dimensional images to be displayed at a longer distance.

The resolution of the reconstructed object from the Fourier hologram that is generated from multiple view images is
analyzed in this paper. We found that the maximum view angle and the wavelength limit the maximum frequency of the
reconstructed object. The relationship between the bandwidth of the object and the lens pitch of the lens array affects the
aliasing of the reconstruction. All these four parameters determine the resolution of the reconstruction from the Fourier
hologram. Based on these analyses, we propose a lens array shift method to enhance the resolution of the reconstructed
object from the Fourier hologram. By shifting the lens array, multiple sets of element images are obtained, and high
spatial density element image is combined from the multiple sets of element images. The resolution enhanced
reconstruction of the object can be obtained from the Fourier hologram of the combined element images. The principles
are verified by experiment.

In this paper, we demonstrate the application of the spiral phase filter for image enhancement in phase shifting digital
holographic microscopy system. The method is based on Fourier plane filtering of the microscopic image with a spiral
phase filter which is located at a computer controlled Spatial Light Modulator (SLM) in the optical imaging pathway of
phase shift digital holographic microscopy system. Spiral phase filter is designed by radial isotropic Hilbert transform.
The spiral phase filter as a spatial filter in Fourier plane of an imaging setup has been proposed as an isotropic edge
detection method providing strong contrast enhancement of microscopic amplitude and phase objects. Since all threedimensional
information is captured by phase shifting digital holographic microscopy, the reconstructed phase object or
cell is reconstructed clearly observed in three-dimension.

In this paper, we use multi-point source illumination to enhance the resolution of digital holographic microscopy without
shifting the CCD camera. The specimen is illuminated from many directions by using multi-point sources which are
easily created by a lens-array. The high frequency information of the specimen can be captured at a fixed position of
CCD camera. All information is then synthesized to increase the resolution.

We propose a method for generating holograms of real existing 3D objects without coherent optical system. Multiple
orthographic view images of the 3D objects are captured under incoherent illumination and Fourier or Fresnel hologram
is synthesized using captured view images. A lens array is used to capture multiple orthographic view images efficiently.
We also present a method enhancing the phase-only Fourier hologram. By applying the constraints to the orthographic
view images and the generated hologram iteratively, the enhanced phase hologram is obtained.

We implemented the dense light field microscopy using the infinity corrected optical system. In the infinity corrected
optical system, the three-dimensional specimen located around the focal plane of the objective is imaged at the
intermediate plane by the combination of the objective and the tube lens. This intermediate image is again imaged by the
micro lens array and captured by the CCD, providing the light field information. We analyzed geometrical structure of
the dense light field microscope for infinity corrected optical system. From the analyzed results, we defined the
characteristic and relationship of each component. Based on this result, we reconstructed various orthographic view
images of the specimen from the captured light field, and also generated the depth slice images using the computational
integral imaging reconstruction principle.

We propose all-in-focus plane reconstruction based on computational integral imaging reconstruction. The depth of the
object is detected by the pixel matching method with proper object mask, and computational integral imaging
reconstruction is performed to get all in focus image. The pixel matching detects the depth of the single plane object by
evaluating the difference between the collected rays. This pixel matching method can be extended to the multiple plane
objects case by the use of the object masking. After each object is identified, the pixel matching is performed to one
object by masking other objects. By repeating this process to all objects, the correct depth of the multiple objects can be
detected. Computational integral imaging reconstruction is performed to all objects with detected depth values, resulting
in all in focus image. From experimental and simulation results, it is confirmed that our

In this paper, the input-output coupler system using two and three Bragg gratings is implemented for optical communication wavelength, i.e. 1550nm, in path-folding and path-shifting type. The grating is designed with 45 degrees fringe slant angle to achieve normal direction input, output coupler. An additional grating at the output coupler makes the total system throughput increase 9% in comparison with two-grating input-output coupler system. With 5x5mm grating size, the total systems throughput can reach nearly 26% for two-grating and 35% for three-grating input-output coupler.

We propose a new synthesis method for the hologram of 3D objects using multiple orthographic view images captured
by lens array. The 3D objects are captured through a lens array under normal incoherent illumination, and their multiple
orthographic view images are generated from the captured image. Each orthographic view image is numerically
overridden by the plane wave propagating at the direction of the corresponding projection angle and integrated into a
single complex value, which constitutes one pixel in the synthesized hologram. By repeating this process for all
orthographic view images, we can generate the Fourier hologram of the 3D objects. Since the proposed method generates
the hologram not from the interference with the reference beam, but from the multiple view images, coherent system is
not required. The manipulation of the 3D information of the objects is also easily achieved in the proposed method. By
manipulating coordinate information of each orthographic view image according corresponding view angle, the depth
order of the reconstructed 3D object can be controlled.

We propose a method generating elemental images for the auto-stereoscopic three-dimensional display technique,
integral imaging, using phase-shifting digital holography. Phase shifting digital holography is a way recording the digital
hologram by changing phase of the reference beam and extracting the complex field of the object beam. Since all 3D
information is captured by the phase-shifting digital holography, the elemental images for any specifications of the lens
array can be generated from single phase-shifting digital holography. We expanded the viewing angle of the generated
elemental image by using the synthetic aperture phase-shifting digital hologram. The principle of the proposed method is
verified experimentally.

A technique displaying arbitrary images based on phase contrast imaging with phase optimization method is proposed.
Phase optimization is performed in a way similar to the iterative Fourier transform algorithm which considers the phase
shift and the aperture size of the phase contrast filter. We test and compare two phase shift cases, which are π/2 and π, in
optimization process. The phase contrast filter at the Fourier plane is implemented using photopolymer whose optically
induced refractive index change has a linear dependence on the illuminating light intensity. As a result, the proposed
method is capable of displaying arbitrary images with enhanced quality and high light efficiency in phase contrast
projection field. Also when the phase contrast filter has π phase shift, the enhancement of the output intensity image is
more obvious.

In this paper, we present a method to extract the text lines in poorly structured documents. The text lines may have
different orientations, considerably curved shapes, and there are possibly a few wide inter-word gaps in a text line. Those
text lines can be found in posters, blocks of addresses, artistic documents. Our method is an expansion of the traditional
perceptual grouping. We develop novel solutions to overcome the problems of insufficient seed points and varied
orientations in a single line. In this paper, we assume that text lines consists of connected components, in which each
connected components is a set of black pixels within a letter, or some touched letters. In our scheme, the connected
components closer than an iteratively incremented threshold will be combined to make chains of connected components.
Elongate chains are identified as the seed chains of lines. Then the seed chains are extended to the left and the right
regarding the local orientations. The local orientations will be reevaluated at each side of the chains when it is extended.
By this process, all text lines are finally constructed. The advantage of the proposed method over prior works in
extraction of curved text lines is that this method can both deal with more than a specific language and extract text lines
containing some wide inter-word gaps. The proposed method is good for extraction of the considerably curved text lines
from logos and slogans in our experiment; 98% and 94% for the straight-line extraction and the curved-line extraction,
respectively.

A fully optical encryption system based on the single-phase encryption method is presented. A two-dimensional array of
real-valued data is phase encoded and scrambled with a random phase key for encryption. The encrypted data is stored
holographically in a DuPont photopolymer, and is reconstructed by conjugate readout. The original data can be retrieved
using a same phase key for decryption and an interferometer for phase-to-intensity conversion. The influence of a limited
bandwidth on the bit-error-rate in the decrypted data is evaluated. With binary data, error-free decryption can be possible
even when a large fraction of encrypted data is lost.

In this paper, we present a floating image system that consists of a stereoscopic display and a two-lens system. A 3-D image is produced inside of the stereoscopic display and that image is projected into the air by the two-lens system. From the experimental results, our proposed system successfully produces the 3-D image, without the distortion and the defects, in midair so that image is a 3-D floating image.

In this paper, the chirp volume grating recorded in photopolymer for the optical demultiplexer is presented. By using the
chirp grating, the spatial distance of fibers can be controllable. The chirp rate of the grating is investigated. As a result
of the experiment, a 51-channel 0.4-nm-spaced demultiplexer with the channel uniformity of 3.5 dB, the 3dB-bandwidth
of 0.12 nm, and the channel crosstalk of -20 dB is experimentally achieved.

An improved image encryption/decryption approach is proposed. In the encryption system, a binary amplitude image is
encoded in the Fourier domain. Then, the encoded image is scrambled with a random binary phase image to produce the
encrypted image. Both the encoding and encryption processes are done electronically. The encrypted image is stored in
an encrypted phase mask of which the transmittance is proportional to the phase components of that image. In the
decryption process, the encrypted phase mask is optically descrambled with another phase mask which has the
transmittance identical to phase components of the random image used in the encryption process. The descrambled field
is inversely Fourier transformed by a Fourier lens in order to reproduce the original image. The simplicity and the
misalignment free characteristics are the most significant advantages of our method. The Fourier encoding process using
an optimization algorithm with iteration technique is discussed in detail. The effect of noise on the quality of the
decrypted image is investigated. The innovation of the system is demonstrated through simulations. The most critical
issue of our technique is that the encryption process requires an optimization search which consumes some computation
time so that the system is expected to be applied for unreal-time applications.

Today, there are many kinds of 3D displays used to produce 3D images but these 3D images are not touchable. Therefore many researchers study how to produce a floating image from 3D image. In floating image display, a large concave mirror or a large lens is used to produce the floating image. However the lens and the concave mirror produce the defected image because magnifications of these two elements are not constant, and an image distance is not linear relationship from an object distance. In this paper we present the stereoscopic floating image system using a stereo display and two lenses. The proposed floating display system provides an impressive feel of depth, and produced image appears to be located in a free space and near the observer. The two-lens system can eliminate all defects of large convex lens because the magnifications are constant and are not related the object distance and the image distance. The experimental result shows that the proposed system successfully makes a touchable stereoscopic floating image.

Diffusion model of monomers in holographic recording media was investigated to determine diffraction efficiency and the effect of the binder structure on holographic recording in an organic-inorganic hybrid photopolymers. Experimental value and rise of diffraction efficiency for the photopolymer films containing different organic sol-gel precursor (TSPEG) were compared with theoretical plot of diffraction intensity growth against recording time based on the first Harmonic diffusion model, using various material parameters, including the monomer diffusion constant, D, polymerization rate, refractive index of monomer, binder, and polymer. The initial rate of polymerizations in the photopolymer films, evaluated by FT-IR method was compared to the polymerization rate obtained from the simulation. Diffusion time of the photopolymer determined from the simulation was a function of TSPEG content, proving that the side chain in the organic hybrid media affect the diffusion of monomer from the dark area of the photopolymer (non-local polymerization).

In this paper, the double-layer gratings recorded in photopolymer films for the optical demultiplexer is presented. The channel spacing of 0.4nm, the channel uniformity of 3.5 dB, the 3dB-bandwidth of 0.12 nm, and the channel crosstalk of -20dB is experimentally obtained.

The number of channels of an optical communication system is increasing rapidly. In this paper, the demonstration of a
130-channel demultiplexer based on the cascaded volume holographic gratings is presented. Those gratings are
recorded separately in 100-μm thickness photopolymer films, which attached on both sides of a glass substrate. They
have different grating periods, slant angles, and center wavelengths. By ultilizing this configuration, the operating
wavelength range of the optical demultiplexer could be expanded, and therefore, the number of channels of the
holographic demultiplexer is increased. As a result of the experiment, a 0.4-nm-spaced demultiplexer with the channel
uniformity of 3.5 dB, the 3dB-bandwidth of 0.12 nm, and the channel crosstalk of -20 dB is experimentally achieved.

Holographic gratings with asymmetric structure are widely used to couple light into and out of waveguides due to
their high diffraction efficiencies and planar packaging. In this paper, a holographic grating coupler based on the
photopolymer has been designed and experimentally demonstrated at wavelength of 405nm. To achieve the high
diffraction efficiencies in the structure, we investigated the optical properties of the coupler according to the
exposure energy at the 405nm wavelength. In the holographic recording for the asymmetrical geometry, we
researched the optical characteristics of the Dupont photopolymer HRF150-38 as the correction of the Bragg angles
shift because of shrinkage factor and the diffraction efficiency. The performance and the optical characteristics of
the coupler using volume holographic grating will discussed in detail.

We present a novel information or key encryption and transmission technique based on phase-shifting digital holography for a security system. Phase-shifting digital holography is used for recording phase and amplitude information on CCD device. 4-step phase-shifting is implemented by moving the PZT mirror with equidistant phase steps of π/2. The information and the key are converted to random phase patterns. Digital hologram in this method is Fourier transform hologram and quantized with 256 gray-level. The basic idea is that we reuse a 256 gray-level digital hologram to encrypt the information or the key with 4-step phase-shifting digital holography. The encrypted binary data/image in the form of digital hologram can be transmitted through communication network, and is reconstructed and decrypted digitally. The simulation shows that the proposed method gives good results for a successive encryption/transmission.

The implemented T-DMB Splicing System provides multimedia service without any discontinuity of video and audio when inserting commercial and specific program while transmitting main DMB broadcasting program. And it can be used for inserting local broadcasting program while retransmitting central broadcasting program. This paper introduces Terrestrial Digital Multimedia Broadcasting (T-DMB) splicing method based on Eureka-147 DAB and presents a new architecture of transmission system for T-DMB Splicing.

In this paper, a fabrication of Gaussian apodized volume gratings for a holographic demultiplexer is presented. The DuPont HRF-150-38 photopolymer is used because of its stability and ease of use. Based on the Gaussian apodized grating, a 42-channel demultiplexer is optically demonstrated. The interchannel spacing, the interchannel cross-talk level and the channel uniformity of 0.4 nm, -30 dB and 1.5 dB, respectively, are obtained.

Monomer diffusion in an organic-inorganic nanocomposite films during the holographic recording was investigated. The photopolymer films with low shrinkage were prepared by dispersing an aromatic methacrylic monomer and a photo-initiator in organic-inorganic hybrid sol-gel matrices. The shrinkage of the photopolymer film and the diffusion of monomers during the holographic recording could be controlled by optimizing the content of an organically modified silica precursor (ORMOSIL) in the sol-gel matrices. The photopolymer film showed high diffraction efficiency (>90%) under an optimized condition. Photo-sensitivity, angular selectivity and application potential for holographic data storage and optical application will be discussed.

Tir- and mono functional monomers were dispersed in a solution of polysulfone in organic solvent containing a photo initiator and other additives. New photopolymer film was prepared by dispersing acrylic monomer in a polysulfone matrix. The Polysulfone was adopted as a binder since it affords transparent thick films with low dimensional changes during holographic recording. Optical property of the photopolymer showed high diffraction efficiency (>90%) under an optimized optical condition at 532nm laser. The angular selectivity for angular multiplexing page oriented holographic memories (POHMs), the maximum diffraction efficiency of the material during holographic recording, the diffraction efficiency of the films as a function of an incident angle of two beams, exposure energy for saturation of the holographic material and application for holographic data storage will be discussed.

The effect of monomer functionality on the diffraction efficiency of the photopolymer containing multi- and monofunctional monomers was investigated. A mixture of tri-, di-, and mono functional monomers were dispersed in a solution of polysulfone dissolved in organic solvent containing a photo initiator. The monomer contents were varied by changing the ratio between them. The average functionality (Fav = Σ φiFi) was determined, where φi is the mol fraction of the monomer with functionality Fi. The holographic recording was performed and diffraction efficiency (η) of each film was determined by using a 532 nm laser. In the photopolymer film having an optimized composition, η was increased within 20 sec and reached a maximum of >90% with an exposure power of 5 mW laser. The rise of η (response time), maximum η, and stability of η value over prolonged recording were dependent on the monomer structure and composition and the average functionality. The result could be ascribed to the reactivity and functionality of monomers under interference light, to generate refractive index contrast.

In this paper, we propose a method to fabricate the grating for a laser diode shaper. During the grating recording, a beam that has polarization mode orthogonal to those of two recording beams is added. The intensity of the additional beam is controlled by a spatial light modulator to provide the spatial variation of intensity modulation, which leads to the difference of the saturation diffraction efficiency. As the results of the experiment, the laser beam shaped by the obtained grating has Gaussian desired profile intensity and is not aberration along the propagation.

In this paper, we design a subwavelength binary grating working as a diffractive polarizing beamsplitter. The polarizing beamsplitter is then optimized by using a genetic algorithm to increase its extinction ratios up to as high as 238 and 82. We use the rigorous coupled-wave analysis method to calculate the parameters of the beamsplitter during the optimizing process.

We propose the fast accessible data storage system using the double side hologram reconstruction scheme which can simultaneously read out holograms using both the forward and phase conjugate reference beams. In this system, digital pages are recorded in the usual manner but are reconstructed in two CCD cameras by the double side hologram reconstruction. As a result, we achieved the speed of two times faster than the conventional readout and the estimated raw BER were 3.09×10-18 (left image) and 4.76×10-16 (right image), respectively.

In this paper, we present a scheme of recording apodized grating using an additional laser beam polarized orthogonally to two recording beams. The additional beam has a function to control beam intensity modulation of the recording beams and, therefore, changes the saturated modulation amplitude of the grating. An investigation of the diffraction efficiency depending on the intensity modulation is implemented in DuPont’s HRF-150-38 photopolymer. As results of the experiment, holographic apodized gratings with uniform, inverse Gaussian, and triangular profiles are fabricated successfully in this material.

Holographic transmission gratings with 0o;-Bragg angle are widely used to couple light into and out of waveguides due to their high diffraction efficiencies and planar packaging. In this paper, a holographic grating coupler based on the photopolymer has been designed and experimentally demonstrated. To achieve the high diffraction efficiencies, we investigate the optical properties of the coupler according to the exposure energy at the 405 nm wavelength. For the asymmetrical geometry with 72othe correction of the Bragg angles shift of about 0.95o; and 3.45o;, which are induced by the 7.86% shrinkage factor, is successfully demonstrated. The performance and the optical characteristics of the coupler using volume holographic grating are discussed in detail.

Organic-inorganic nanocomposite films were prepared by dispersing an aromatic methacrylic monomer and a photo-initiator in organic-inorganic hybrid sol-gel matrices. The film properties could be controlled by optimizing the content of an organically modified silica precursor (TSPEG) in the sol-gel matrices. The photopolymer film modified with the organic chain (TSPEG) showed high diffraction efficiency (>90%) under an optimized condition. In addition, we implement a digital holographic security system that combines the electrical biometrics technology with fully digital holographic storage using an organic-inorganic hybrid type photopolymer film.

Liquid crystalline compounds with a siloxane component in the tail were found to be effective in the formation of holographic gratings of polymer dispersed liquid crystal systems over a wide concentration range from 3wt% to 30wt%. The structure of the siloxane chain had a big effect on the performance of the gratings. Fine gratings with a diffractive efficiency of 40wt% could be formed with a liquid crystalline compound containing 3wt% disiloxane.

Fabricating holographic apodized gratings is often impeded by nonlinear property of materials, which makes the resultant profile out of expectation. In this paper, the new scheme to fabricate Gaussian apodized grating is proposed. Instead of fixed Gaussian recording beams, recording beam profiles that can compensate the nonlinear sensitivity of the material at low recording intensities are created by a gray level spatial light modulator (SLM). DuPont’s HRF-150-38 photopolymer is chosen because of its stability and ease to use. As the first result of the experiment, a Gaussian grating of 2.7±0.02mm standard deviation is recorded at 0.3mW/cm2 recording intensity after exposure of 300 seconds.

Optimization of performance of holographic gratings was investigated by changing the chemical structures of photopolymerizable monomers, the LC content, and recording beam intensity, which strongly related to the control of kinetics of polymerization and phase separation of LCs. High diffraction efficiency was obtained using 3-acryloxypropyltrimethoxysilane (APTMS) and 2-[(3,4-epoxycyclohexyl)ethyl]trimethoxysilane (ECTMS) as siloxane-containing reactive diluent by inducing a fast and good phase separation originated from the incompatible and flexible properties of siloxane chain even at a very low LC concentration (10~25wt%), in contrast to the case using diluent without siloxane component, like N-vinylpyrrolidinone. The phase-separated morphologies of gratings, such as spacing and surface topology, were observed by atomic force microscopy (AFM). Very regular and smooth morphologies were observed for the formed holographic gratings with APTMS and various amounts of LC.

Optical transparency and high diffraction efficiency are two essential factors for high performance of the photopolymer. Optical transparency mainly depends on the miscibility between polymer binder and photopolymerized polymer, while diffraction efficiency depends on the refractive index modulation between polymer binder and photopolymerized polymer. For most of organic materials, the large refractive index difference between two polymers accompanies large structural difference that leads to the poor miscibility and thus poor optical quality via light scattering. Therefore, it is difficult to design a high-performance photopolymer satisfying both requirements. In this work, we prepared a new phase-stable photopolymer with large refractive index modulation and investigated the optical properties. Our photopolymer is based on modified poly (methyl methacrylate) as a polymer binder, acryl amide as a photopolymerizable monomer, triethanolamine as initiator, and yellow eosin as a photosensitizer at 532nm. Diffraction efficiency over 85% and optical transmittance over 90% were obtained for the photopolymer.

A new structure of polarization-selective elements consisting of two holographic gratings and a dove prism coupler is proposed. The absence of a multi-stage wave-guide, compact size, and lightweight volume are the outstanding features of the new structure. Based on the coupled-wave theory, the analysis and design of the structure are discussed in detail to calculate the required index modulation. Several parameters such as the recording intensity, the exposure time, and the recording angles for the fabrication of the proposed element are determined. Under the conditions the element is fabricated in Dupont photopolymer HRF-150-38 material and with the operating wavelength of 532nm. A simplified pick-up head is constructed to evaluate the performance of the fabricated element.

Organic-inorganic nanocomposite films were prepared by dispersing an aromatic methacrylic monomer and a photo-initiator in organic-inorganic hybrid sol-gel matrices. The film properties could be controlled by optimizing the content of an organically modified silica precursor (TSPEG) in the sol-gel matrices. The photopolymer film modified with the organic chain (TSPEG) showed high diffraction efficiency (>90%) under an optimized condition. High diffraction efficiency could be ascribed to the fast diffusion and efficient polymerization of monomers under interference light to generate refractive index modulation. The TSPEG modified photopolymer film could be successfully used for holographic memory. Angular selectivity of the film were 0.46 ~ 0.16 depending on the film thickness in the incident angles between 20° ~ 70°. A digital holographic image and a real object were recorded successfully in the photopolymer film.

A Gaussian apodization technique applied to a transmission volume hologram for a holographic demultiplexer is proposed. A Gaussian apodized grating 15×11 mm in size, 38 µm thick, and with a 3.2-mm horizontal standard deviation of the modulating index profile is fabricated. A 22-channel demultiplexer based on that grating has been optically demonstrated. Channel spacing, interchannel crosstalk level, and channel uniformity of 0.8 nm, –30 dB, and 1.5 dB, respectively, are obtained. In addition, an insertion loss of 13 dB, which is caused by the primary limitation of this technique, is observed.

To reduce computation time, a new approach for designing computer-generated holograms is proposed. In this new method, we utilize artificial neural networks to initiate the genetic algorithm, so that the high computation cost of genetic algorithms for synthesizing holograms is significantly reduced, while the high diffraction efficiency and uniformity are still ensured. Designed binary phase holograms have a diffraction efficiency of 75.8% and uniformity of 5.8%, which are proven in computer simulation and experimentally demonstrated.

In order to reduce the computation time, a new approach for designing computer-generated holograms is proposed. In this new method, we utilize artificial neural network to initiate the genetic algorithm so that the high computation cost of genetic algorithm for synthesizing holograms is significantly reduced while the high diffraction efficiency and uniformity are still ensured. Designed binary phase holograms have the diffraction efficiency of 75.8% and uniformity of 5.8%, which are proven in computer simulation and experimentally demonstrated.

We analyze the thermal properties of the DuPont HRF150-38 photopolymer for digital holographic card manufacture. In case of recording after heating, the diffraction efficiency of the hologram is more than 70% at 100°C but is decreased exponentially at temperatures over 100°C. It is observed in the recording before heating that the diffraction efficiency of the hologram fixed by a UV light is increased to approximately 10% at 100°C, but the hologram are erased at temperatures over 120°C.

In this paper, the implementation of Gaussian apodized volume grating for a demultiplexer is presented. A 42-channel demultiplexer based on that grating is optically demonstrated. By using the Gaussian apodized grating, the crosstalk level between two channels is reduced down to -35dB. The bandwidth of a channel is 0.18 nm. The two adjacent fibers are seperated by 122.5-μm horizontal distance providing the wavelength spacing between each channel of 0.4 nm. Besides, for all 42 channels, the interchannel uniformity of 1.5 dB has been obtained.

We propose the double-side dual hologram reconstruction scheme which can simultaneously read out holograms using both the forward and phase conjugate reference beams, and demonstrate stereo image recording and playback by the holographic memory system. This system is composed of a stereoscopic camera obtained stereo image pairs, holographic data storage where stereo images are recorded in the usual manner but read out by double-side dual reconstruction, and a stereo monitor that use polarized light techniques. As a result, stereo digital pages, which are reconstructed by the proposed double-side dual reconstruction method, can be obtained with very low cross talk noise, and the estimated raw BER of retrieved holograms were approximately 3.59×10-4 (left image) and 5.0×10-4 (right image), respectively.

The parallel stereoscopic camera has a linear relationship between vergence and focus control. We introduced the automatic control method for a stereoscopic camera system that uses the relationship between vergence and focus of a parallel stereoscopic camera. The automatic control method uses disparity compensation of the acquired image pair from the stereoscopic camera. For faster extraction of disparity information, the proposed binocular disparity estimation method by the one-dimensional cepstral filter algorithm would be investigated. The suggested system in this study greatly reduces the extraction time requirement and error so as to offer spontaneous control and greater real-time realism to acquire high quality stereoscopic images.

In this paper, Gaussian apodization technique applied to a transmission volume hologram for holographic demultiplexer is proposed. The Gaussian apodized grating of 15 mm x 11 mmsize, 38 μm thickness and 3.2 mm horizontal standard deviation of the modulating index profile was fabricated. A 22-channel demultiplexer based on that grating has been optically demonstrated. The channel spacing, the interchannel cross-talk level and the channel uniformity of 0.8 nm, -30 dB and 1.5 dB, respectively, were obtained.

A new approach to design the binary phase holograms, which is of less computation time and equal efficiency compared with the genetic algorithm method is proposed. Synthesized holograms having diffraction efficiency of 75.8% and uniformity of 5.8% are proven in computer simulation and experimentally demonstrated.

In this paper, to reduce the Bragg-mismatch problem of the dual-wavelength method, we record the hologram in the Dupont's photopolymer of thickness L=38μm and use a digital image data which has 78×104 bit/page. Also, to compensate the image magnification problem, a pair of cylinder lens consisting of 4F system behind the F2 lens and proposed data matrix image processing technique is used. As a result, the raw BER through Gaussian fitting after extracting binary data is around 3.09×10-6.

In this paper, we demonstrate the holographic smart card system using digital holographic memory technique that uses reference beam encrypted by the random phase mask to prevent unauthorized users from accessing the stored digital page. The input data that include document data, a picture of face, and a fingerprint for identification is encoded digitally and then coupled with the reference beam modulated by a random phase mask. Therefore, this proposed system can execute recording in the order of MB~GB and readout all personal information from just one card without any additional database system. Also, recorded digital holograms can't be reconstructed without a phase key and can't be copied by using computers, scanners, or photography.

A new beam steering scheme using computer-generated holograms(CGHs) is proposed. The steering devices in order to control the reference and object wave are necessary in various holographic multiplexing methods. The beam steering device using CGHs can be simultaneously processed the coarse address function controlling the beam up or down so as to select slice and the fine address function adjusting to the particular holographic page within the chosen layer. From the experimental results, we show that the beam steering can be easily implemented and so powerful to generate the electrically addressed reference wave in digital holographic memory system.

Parallel stereoscopic camera has a linear relationship between vergence and focus control. We introduced the automatic control method for a stereoscopic camera system that uses the relationship between vergence and focus of a parallel stereoscopic camera. The automatic control method uses disparity compensation of the acquired image pair from the stereoscopic camera. For faster extraction of disparity information, the proposed binocular disparity estimation method by the one-dimensional cepstral filter algorithm would be investigated. The suggested system in this study substantially reduced the controlling time and error-ratio so as to make it possible to achieve natural and clear images.

A 42-channel demultiplexer using a volume holographic grating formed in photopolymer medium for dense wavelength division multiplexing (DWDM) applications is experimentally demonstrated for the first time. A 3dB bandwidth of 0.18nm and channel crosstalk of -20dB for a 50GHz channel spacing, is reported.

In spatial multiplexing method, the steering devices for reference wave and object wave are necessary. A new scheme applying computer-generated holograms(CGHs) to the steering device is proposed. The beam steering device using CGHs can be performed simultaneously the coarse address function directing the reading or writing beams to the suitable layer and the fine address function corresponding to the particular holographic page within the chosen common volume unit. This new scheme is compared with both the beam steering method using spatial/angular multiplex AODs and the mechanically steered method in terms of access time, cost, and efficiency.

Multi-phase and binary-phase computer-generated holograms were designed and demonstrated for full-color image generation. Optimize a phase profile of the hologram that achieves each color image, we employed a simulated annealing method. The design binary phase hologram had the diffraction efficiency of 33.23 percent and the reconstruction error of 0.367 X 10-2. And eight phase hologram had the diffraction efficiency of 67.92 percent and the reconstruction error of 0.273 X 10-2. The designed BPH was fabricated by micro photolithographic technique with a minimum pixel width of 5micrometers . And the it was reconstructed using by two Ar-ion lasers and a He-Ne laser. In addition, the color dispersion characteristic of the fabricate grating and scaling problem of the reconstructed image were discussed.

Holographic multi-channel demultiplexer for the wavelength division multiplexing optical transmission system has been experimentally demonstrated by using photorefractive lithium niobate crystals doped with iron. As a proof of our scheme, we have designed the 8-channel demultiplexer with a channel spacing of 0.8 nm, and some preliminary experimental results are presented and discussed.

A novel photorefractive demultiplexer for dense wavelength division multiplexing (DWDM) applications has been experimentally demonstrated for the first time, by using the narrow-band filtering and demultiplexing properties of a volume holographic gratings formed in lithium niobate crystal. For the multiple recording of the 16-wavelength channels with equal diffraction efficiency, the rotation multiplexing and the exposure time schedule are used. The 1x16 photorefractive DMUX is designed to work with a channel spacing of 0.5nm range from 670nm to 677.5nm and a bandwidth of 0.16nm. From the experimental results, the measured diffraction efficiency of each channel is 8.3+/- 0.62%. The 3dB bandwidth of 0.16+/- 0.005nm and the channel spacing of 0.46 approximately 0.5nm, with optical loss from Fresnel reflection and absorption in the crystal of 2.22dB/cm, are measured.

The polarization properties of the reflection-type holographic recording material, DuPont photopolymer OmniDexTM 706, have been studied. Depending on the position of photopolymer-Mylar assembly, linearly polarized laser beam alters its polarization state about 40%. Due to the birefringence of Mylar substrate, this phenomenon has been occurred very randomly through a wide range and affected in diffraction efficiencies. In the case of reflection-type hologram, the directions of two beams incident onto the recording materials are not same, the change of the polarization states cause the weak fringe visibility. As a result, reflection holograms have shown low diffraction efficiencies and unstable characteristics.

The independent characteristic of the angular selectivity for the writing conditions was presented in photorefractive grating. In general, the incident angle of writing beam and the interaction length determine the angular selectivity of the grating. When the focused probe beam is incident on the grating, we obtain a new relation that the angular selectivity of the photorefractive grating depends on the probe beam incident conditions and is independent of the writing conditions such as writing beam incident angle, wavelength, and interaction length. These characteristics are experimentally investigated as a function of the following parameters; writing beam incident angle, probe beam width and lens focal length. In the experimental results, it has demonstrated that the control parameters are not the incident angles of writing beam but the probe beam width and focal length of the convex lens. Another property of this configuration is to have same value within large angular range that is also determined by the readout conditions.

In this paper, gratings to apply for the optical interconnection are designed using a genetic algorithm (GA) for a robust and efficient schema. The real-time optical interconnection system architecture is composed with LC-SLM, CCD array detector, IBM-PC, He-Ne laser, and Fourier transform lens. A pixelated binary phase grating is displayed on LC-SLM and could interconnect incoming beams to desired output spots freely by real-time. So as to adapt a GA for finding near globally-cost solutions, a chromosome is coded as a binary integer of length 32 X 32, the stochastic tournament method for decreasing the stochastic sampling error is performed, and a single-point crossover having 16 X 16 block size is used. The characteristics on the several parameters are analyzed in the desired grating design. Firstly, as the analysis of the effect on the probability of crossover, a designed grating when the probability of crossover is 0.75 has a 74.7[%] high diffraction efficiency and a 1.73 X 10-1 uniformity quantitatively, where the probability of mutation is 0.001 and the population size is 300. Secondly, on the probability of mutation, a designed grating when the probability of mutation is 0.001 has a 74.4[%] high efficiency and a 1.61 X 10-1 uniformity quantitatively, where the probability of crossover is 1.0 and the population size is 300. Thirdly, on the population size, a designed grating when the population size is 300 and the generation is 400 has above 74[%] diffraction efficiency, where the probability of mutation is 0.001 and the probability of crossover is 1.0.

A new tuning scheme of the photorefractive filter is presented using LiNbO3 crystal doped with 0.015Wt.% Fe. Analyzing the filter bandwidth property from the geometrical method, a new wavelength selectivity theory is derived. The center wavelength can be tuned by the real-time received beam angle control using the spatial light modulator. As tuning time depends on the response time of the spatia light modulator, it has high tuning speed. The use of thermally fixed single grating makes the uniform diffraction property over all filtering range. Designed tunable filter consists of the three channel with 4 nm bandwidth and 10 nm spacing. From the optical experiment, we get the real-time tunable filter which has 4.5 nm, 4.25 nm, 4 nm bandwidth and 1530.5 nm, 1540.5 nm, 1549.5 nm center wavelength, respectively. Demonstrated filter has a switching time of several tens milli-second and a full tuning range of 20 nm.

In the photorefractive wavelength selective filter, a new tuning scheme is proposed and optically demonstrated. Center wavelength of photorefractive optical filter can be tuned in an electronics speed with a special optical system having LC-SLM and positive lens. Preliminary experimental results in proposed scheme are given, and compared with theoretical values.

The diffraction efficiencies of DuPont's photopolymer OmniDexR 706 holographic recording material are measured for exposures, incident angles, diffusion-time delays and exposure times. As attaching the material on a glass or plastic plate, unwanted secondary gratings are induced, which make the diffraction efficiencies much lower than expected. In order to eliminate this phenomenon, we change the incident angle between the object beam and the reference beam. Since the polymerization and the photospeed of photopolymers are 1000 times slower than silver halide materials, holograms can be influenced with many kinds of parameter. It was examined the static characteristics and the dynamic characteristics that are related with an exposure time and a diffusion-time delay using the dark reaction of monomer in polymerization. Applying the dynamic characteristics, the diffraction efficiencies of this material were stabilized. As a result, the best condition is achieved when the total input power is 8 mW [exposure energy is 200 (mJ/cm2) in our experiment] and the diffusion-time delay is from one to three minute.

The interaction between two incident beams in a photorefractive Cu-doped (Cu-KNSBN) crystal is investigated at 632.8nm He-Ne laser wavelength. In addition, the coherent two-wave coupling properties of a photoinduced volume refractive-index phase grating in the presence of amplitude modulation on the signal beam are also experimentally investigated as a function of the intensity ratio of the two incident beams. Some preliminary experimental result are presented for use as a dynamic photorefractive beam-splitter and pulse shaping element in coherent optical communication systems and in optical signal processing.

We propose the noble method of 3D optical implementation for the multiplication of a matrix by a vector by using the binary phase hologram array designed by computer. The elements of the matrix are transformed into the form of the spatial frequency in the hologram. The fabrication of the hologram is done by the photo-lithographic technique.

As the interest of holographic stereogram in the 3D displays is increased, the application of this technique has been suggested in several fields. Especially, in architecture, 3D bird's-eye view can be replaced instead of building models. In this paper, the possibility of application is proposed and demonstrated it in architectural perspective presentation. Using computer graphics, we can create an object that has 3D information, but it is only 2D when projected on a screen or CRT. Dividing these computer- generated graphic objects into several views aspects (2D images) and then synthesize them onto holographic film. A geometrical method is used to calculate sampling angles, and a TFT LCD is used to display the 2D images. Using a big size of collimating mirror and films, we made a holographic stereogram, which is 600 X 400 mm2.

Sampling method for making 3D animation using computer animation data is presented. Computer animation data has 3D information and displayed with 2D images on the screen or CRT. We divide these 3D animation data into several aspect of views (2D images) and synthesize onto holographic film. After chemical processing we can see 3D images the same as what they have when they are made. Also, using the TFT LCD (liquid crystal device), holographic stereograms can be made easily. In this paper, geometrical method is used in order to easily calculate the sampling angles and TFT LCD to display the 2D images. Experimental results show that this method is very tolerable to be shown with 17 degree for several people. In addition, with these series of stereograms and holographic screen, the 3D movie will be possible.

Simpler and easier sampling method which is one of the most important parameter required for making holographic stereograms is presented to reconstruct the images from transfer hologram. Instead of fringe-by-fringe sampling method which is difficult to apply in recording holographic stereograms, a new geometrical method is proposed for easier calculation of the sampling numbers. When the slit size is fixed under human pupil size, one can see the full 2D image through a slit. Dividing the distance between the two pupils by slit size, it determines the sampling numbers which are needed for recording. The angle difference of the real object becomes a binocular parallax. And the series of these 2D images are recorded on the master hologram. After processing, it transfers to transfer hologram. As a result, two images which exactly correspond to the places of viewer's eyes can be seen simultaneously. Because the object is taken at different angle and these two images are observed simultaneously, it makes us feel as a real object.

A new analysis of the reversal bleaching mechanism and the catalytic reaction of exposure quantity in silver halide holographic diffraction gratings is presented. It is turned out that the exposure quantity reacts as a catalyst in the developing process and makes the velocity of developing reaction time fast. The experimental investigation has revealed that the holographic phase gratings with high diffraction efficiencies (> 70%) could be taken, if the developing reaction time be optimized in the 50 approximately 350 [(mu) J/cm2] range of exposure quantity.

In this paper, we newly apply a genetic and simulated annealing hybrid heuristic to encode optimal filter for optical pattern recognition. Simulated annealing as a stochastic computational technique allows for finding near globally-minimum-cost solutions with cooling schedule. Using the advantages of a parallelizable genetic algorithm (GA) and a simulated annealing algorithm (SA), the optimum filters are designed and implemented. The filter having 128 multiplied by 128 pixel size consists of the stepped phase that causes the discrete phase delay. The structure of this can be divided into rectangular cells such that each cell imparts a discrete phase delay of 0 approximately equals 2 pi[rad] to the incident wave front. Eight-phase stepped filters that we designed are compared with phase only matched filter and cosine-binary phase only filter. It is deeply focused on investigating the performance of the optimum filter in terms of recognition characteristics on the translation, scale and rotation variations of the image, and discrimination properties against similar images. By GA/SA hybrid heuristic, the optimum filter is realized for high efficiency optical reconstruction in spite of decreasing iteration number needed to encode it by respective algorithms.

Dynamic free-space optical routing system is experimented by a holographic crossbar with single-stage switching architecture. For dynamic operation, electrically addressed liquid- crystal spatial light modulator and diffraction gratings are used in place of passive holograms. Diffraction gratings are consisted of regular cells and have multiple phase delays. This pixelated kinoform phase grating array displayed on SLM deflects a input beam toward a wanted direction or splits a input beam into many beams and then steers them to desired positions. Each grating array is combined with three periods of grating which is constructed by 32 X 32 pixels with equally space phase levels. This system has higher efficiencies and superior characteristics of beam split, and produces asymmetric output beam pattern. In this system, input ports are 3 X 3 and output ports are 5 X 5. It operates at high speed as dynamic free-space optical switch and leads low optical losses.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Keywords/Phrases

Keywords

in

Remove

in

Remove

in

Remove

+ Add another field

Search In:

Proceedings

Volume

Journals +

Volume

Issue

Page

Journal of Applied Remote SensingJournal of Astronomical Telescopes Instruments and SystemsJournal of Biomedical OpticsJournal of Electronic ImagingJournal of Medical ImagingJournal of Micro/Nanolithography, MEMS, and MOEMSJournal of NanophotonicsJournal of Photonics for EnergyNeurophotonicsOptical EngineeringSPIE Reviews